Protective gas composition for magnesium/magnesium alloy production and combustion preventing method

Abstract

There is provided a protective gas composition for preventing combustion of a molten magnesium/magnesium alloy, containing a compound selected from the group consisting of 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,3,3,3-tetrafluoropropene (OHFC-1234ze), methyl 1,1,2,2-tetrafluoroethyl ether (HFE-254pc), which are fluorine-containing organic compounds, and mixtures thereof; and a carrier gas.

1. A method for preventing combustion of a molten magnesium/magnesium alloy in a magnesium or magnesium alloy production, comprising allowing a gas composition comprising:
 a protective gas that is a compound selected from the group consisting of 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,3,3,3-tetrafluoropropene (OHFC-1234ze), methyl 1,1,2,2-tetrafluoroethyl ether (HFE-254 pc), and mixtures thereof; and 
 a carrier gas, 
 
       to flow onto a surface of the molten magnesium/magnesium alloy molten at 600-850° C.,
 wherein the gas composition is allowed to flow at a flow velocity that is sufficient for producing ignition proof effect, in a range of 5-5000 mL/min/m 2  in protective gas flow rate per molten metal unit area. 
 
     
     
       2. A method according to  claim 1 , wherein the carrier gas is selected from the group consisting of dry air, carbon dioxide, argon, helium, neon, krypton, xenon, nitrogen, and mixtures thereof. 
     
     
       3. A method for preventing combustion of a molten magnesium/magnesium alloy in a magnesium or magnesium alloy production, comprising allowing a gas composition comprising:
 a protective gas that is a compound selected from the group consisting of 1,1,1,3,3-pentafluoropropane (HFC-245fa), 1,3,3,3-tetrafluoropropene (OHFC-1234ze), methyl 1,1,2,2-tetrafluoroethyl ether (HFE-254 pc), and mixtures thereof; and 
 a carrier gas, 
 
       to flow onto a surface of the molten magnesium/magnesium alloy molten at 600-850° C.
 wherein the gas composition is allowed to flow at a flow velocity that is sufficient for producing ignition proof effect for 180 seconds or longer when molten metal is open, in a range of 0.005-5 volume % in protective gas concentration in the carrier gas and/or 5-5000 mL/min/m 2  in protective gas flow rate per molten metal unit area. 
 
     
     
       4. A method according to  claim 3 , wherein the carrier gas is selected from the group consisting of dry air, carbon dioxide, argon, helium, neon, krypton, xenon, nitrogen, and mixtures thereof.